Babel allows you to code using the newest language features, but "compile" down to older versions of javascript for deployment so you can run on older browsers

Babel allows you to code using the newest language features, but "compile" down to older versions of javascript for deployment so you can run on older browsers (possible since JavaScript is Turing complete so you can replace the new-fancy features with less-pretty/less-readable code that does the same thing) Eslint is a linter. Prettier is a code formatter. Yarn is a dependency manager. Webpack is a bundler for JavaScript files - think of it as conceptually like a linker for C++ et al. Nothing too different from any other language (apart from babel perhaps), and none of them are essential or required (unlike linkers in C/C++ for example)